BIOLOGICAL ACTIVITY OF Bacillus thuringiensis CULTURE SUPERNATANT ON Bemisia tabaci AND ITS PARASITOID Eretmocerus eremicus

Abstract

The effects of Bacillus thuringiensis culture supernatants and their derived products were evaluated on whitefly Bemisia tabaci and its parasitoid Eretmocerus eremicus. Evaluated variables on B. tabaci included adult repellence, oviposition deterrence and nymphal mortality. The most active products were evaluated on mortality of E. eremicus. Residual solid of strain ITCBT62 supernatant showed significant effects on adult repellence (RI, 0.42) and oviposition deterrence (ODI, -70.1). Residual solid of strain ITCBT62 supernatant and ethanol extract of strain ITCBT61 supernatant caused higher mortality of B. tabaci nymphs (53.8 % and 51.2 %, respectively). None of these supernatant derived products had toxic effects on the parasitoid E. eremicus. The analysis of ethanol extract of strain ITCBT61 supernatant by liquid chromatography/high resolution mass spectrometry (LC-HRMS) showed the presence of various compounds, with one particularly abundant metabolite of molecular formula C15H20N2O, which has not been previously reported as product of the liquid culture of B. thuringiensis.